Custom UUID for multiple Bluetooth connection in Android

Question

I have an android device acting as server which connects to multiple bluetooth android clients. I understand the concept of UUID and how it is unique.

My question is, c

Answer 1

You can generate one like this. First, is needed to generate as long the 64 least and most significant bits:

private static long get64LeastSignificantBitsForVersion1() {
    Random random = new Random();
    long random63BitLong = random.nextLong() & 0x3FFFFFFFFFFFFFFFL;
    long variant3BitFlag = 0x8000000000000000L;
    return random63BitLong + variant3BitFlag;
}
 
private static long get64MostSignificantBitsForVersion1() {
    LocalDateTime start = LocalDateTime.of(1582, 10, 15, 0, 0, 0);
    Duration duration = Duration.between(start, LocalDateTime.now());
    long seconds = duration.getSeconds();
    long nanos = duration.getNano();
    long timeForUuidIn100Nanos = seconds * 10000000 + nanos * 100;
    long least12SignificatBitOfTime = (timeForUuidIn100Nanos & 0x000000000000FFFFL) >> 4;
    long version = 1 << 12;
    return 
      (timeForUuidIn100Nanos & 0xFFFFFFFFFFFF0000L) + version + least12SignificatBitOfTime;
}

next you can use the above methods to build one UUID:

public static UUID generateType1UUID() {
 
    long most64SigBits = get64MostSignificantBitsForVersion1();
    long least64SigBits = get64LeastSignificantBitsForVersion1();
 
    return new UUID(most64SigBits, least64SigBits);
}

Answer 2

Answer:

I finally found out that you can use a custom UUID using a generator and it works with multiple devices. The UUID must be unique and should not collide with the ones that are common & public. Hopefully someone finds it useful